I bought a Kokopelli Nirvana late last year and just took it out for the first time last month. We backpacked down Dark Canyon and packrafted the Colorado down to Hite. There were 4 Nirvanas in our group and everyone was very pleased. We got hit with 50+ mph wind gusts for about 12 of the 14 miles out to Hite. It was kind of freaky to be out in the river in that tiny boat in all of that, but it held up fine. I even had a dog on my lap.
I'd still choose an Alpacka over it due to the weight, but if you're okay with an extra pound or two and don't have the Alpacka in the budget, it's a great boat. With all that said, my Kokopelli us for sale in the classifieds section. I'm 6'4" and the large is smaller than I'd like. That and I just ordered my first big raft, much thanks to all the info I found here on the buzz.
Here's a couple shots of our Kokopellis in Cataract last month: